1. Field
Embodiments of the present invention relate to an electro-hydraulic brake and a control method thereof which provide hydraulic braking force to transfer a stable pedal feel and provide regenerative braking to improve fuel efficiency.
2. Description of the Related Art
Recently, hybrid vehicles, fuel cell vehicles and electric vehicles to improve fuel efficiency and to reduce exhaust gas have been vigorously developed. In each of such vehicles, a braking device, i.e., a brake for vehicles is essentially installed. Such a brake for vehicles is referred to a device functioning to decelerate or stop a driving vehicle.
In general, brakes for vehicles are classified into a vacuum brake generating braking force using suction pressure of an engine, and a hydraulic brake generating braking force using hydraulic pressure.
The vacuum brake exhibits large braking force with a little force using a difference between suction pressure of a vehicle engine and atmospheric pressure in a vacuum booster. That is, the vacuum brake generates greater output than force applied to a brake pedal when a driver presses the pedal.
In such a conventional vacuum brake, suction pressure of the vehicle engine needs to be supplied to the vacuum booster to form a vacuum, and thus fuel efficiency may be reduced. Further, the engine needs to be operated at all times to form the vacuum even when the vehicle is stopped.
Further, since a fuel cell vehicle or an electric vehicle does not include an engine, the conventional vacuum brake amplifying foot effort of a driver during braking is not applicable to the fuel cell vehicle or the electric vehicle. Moreover, since a hybrid vehicle executes an idle rotation stopping function during stoppage to improve fuel efficiency, introduction of the hydraulic brake into the hybrid vehicle is required.
That is, all vehicles require implementation of regenerative braking to improve fuel efficiency, as described above, and thus implementation of regenerative braking is facilitated by introduction of the hydraulic brake.
In the case of an electro-hydraulic brake which is a kind of hydraulic brake, when a driver presses a pedal, a controller senses pressing of the pedal, supplies hydraulic pressure to a master cylinder, and transmits braking hydraulic pressure to wheel cylinders of respective wheels to generate braking force.
Such an electro-hydraulic brake is configured to be easily controllable, but an improved electro-hydraulic brake satisfying user requirements, such as safety of a vehicle during braking, improvement of fuel efficiency, proper pedal feel, etc., is needed.
Therefore, research and development of an electro-hydraulic brake having a simple configuration, providing braking force even when malfunction occurs and being easily controlled is underway.